Brochure: Disinfection by-products in drinking water

PDF Version (963 KB, 1 page)

Chlorine is the most commonly used drinking water disinfectant. It has been used to disinfect water and make it suitable for drinking for more than 100 years. It has nearly eliminated diseases like typhoid fever, cholera, and dysentery in Canada.

The benefits of disinfecting drinking water with chlorine are much greater than the potential health risks of being exposed to higher levels of disinfection by-products.


Disinfection by-products called trihalomethanes (THMs) and haloacetic acids (HAAs) are formed naturally when chlorine in water combines with organic matter like leaves or other vegetation

THM and HAA levels tend to increase in the summer and fall

You don't have to stop using tap water. You can still brush your teeth, wash fruits and vegetables, use tap water to prepare foods, and wash dishes and clothes

You would have to be exposed to high levels of disinfection by-products over many years for your health to be at risk

You can be exposed by drinking or bathing in affected water or breathing in steam when showering

Related links

Did you find what you were looking for?

What was wrong?

You will not receive a reply. Don't include personal information (telephone, email, SIN, financial, medical, or work details).
Maximum 300 characters

Thank you for your feedback

Date modified: